US9610724B2 - Device for injection molding a preform - Google Patents

Device for injection molding a preform Download PDF

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Publication number
US9610724B2
US9610724B2 US14/355,404 US201214355404A US9610724B2 US 9610724 B2 US9610724 B2 US 9610724B2 US 201214355404 A US201214355404 A US 201214355404A US 9610724 B2 US9610724 B2 US 9610724B2
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United States
Prior art keywords
resin
flow channel
preform
intermediate layer
layer
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US14/355,404
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US20140287079A1 (en
Inventor
Hiroshi Hosokoshiyama
Mamoru Sato
Yasuhiro Ishizawa
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Yoshino Kogyosho Co Ltd
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Yoshino Kogyosho Co Ltd
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Assigned to YOSHINO KOGYOSHO CO., LTD. reassignment YOSHINO KOGYOSHO CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ISHIZAWA, YASUHIRO, SATO, MAMORU, HOSOKOSHIYAMA, HIROSHI
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    • B29C49/221—
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/16—Making multilayered or multicoloured articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/16—Making multilayered or multicoloured articles
    • B29C45/1603—Multi-way nozzles specially adapted therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/16—Making multilayered or multicoloured articles
    • B29C45/1642—Making multilayered or multicoloured articles having a "sandwich" structure
    • B29C45/1646—Injecting parison-like articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/20—Injection nozzles
    • B29C49/0078—
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
    • B29C49/22—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor using multilayered preforms or parisons
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B11/00—Making preforms
    • B29B11/06—Making preforms by moulding the material
    • B29B11/08—Injection moulding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B11/00—Making preforms
    • B29B11/06—Making preforms by moulding the material
    • B29B11/10—Extrusion moulding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B11/00—Making preforms
    • B29B11/14—Making preforms characterised by structure or composition
    • B29B2911/00—
    • B29B2911/1404—
    • B29B2911/14046—
    • B29B2911/14073—
    • B29B2911/14086—
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    • B29B2911/141—
    • B29B2911/14133—
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/16—Making multilayered or multicoloured articles
    • B29C45/1642—Making multilayered or multicoloured articles having a "sandwich" structure
    • B29C45/1646—Injecting parison-like articles
    • B29C2045/1648—Injecting parison-like articles the parison core layer being a barrier material
    • B29C2049/0089—
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
    • B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
    • B29C2049/023—Combined blow-moulding and manufacture of the preform or the parison using inherent heat of the preform, i.e. 1 step blow moulding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/07—Preforms or parisons characterised by their configuration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/07—Preforms or parisons characterised by their configuration
    • B29C2949/0715—Preforms or parisons characterised by their configuration the preform having one end closed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/07—Preforms or parisons characterised by their configuration
    • B29C2949/074—Preforms or parisons characterised by their configuration having ribs or protrusions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/07—Preforms or parisons characterised by their configuration
    • B29C2949/075—Preforms or parisons characterised by their configuration having at least one internal separating wall
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/07—Preforms or parisons characterised by their configuration
    • B29C2949/079—Auxiliary parts or inserts
    • B29C2949/08—Preforms made of several individual parts, e.g. by welding or gluing parts together
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/20—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer
    • B29C2949/28—Preforms or parisons whereby a specific part is made of only one component, e.g. only one layer at bottom portion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/30—Preforms or parisons made of several components
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/30—Preforms or parisons made of several components
    • B29C2949/3006—Preforms or parisons made of several components having tangentially different components within one layer, e.g. longitudinal stripes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/30—Preforms or parisons made of several components
    • B29C2949/3012—Preforms or parisons made of several components at flange portion
    • B29C2949/3014—Preforms or parisons made of several components at flange portion partially
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/30—Preforms or parisons made of several components
    • B29C2949/3016—Preforms or parisons made of several components at body portion
    • B29C2949/3018—Preforms or parisons made of several components at body portion partially
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/30—Preforms or parisons made of several components
    • B29C2949/302—Preforms or parisons made of several components at bottom portion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/30—Preforms or parisons made of several components
    • B29C2949/302—Preforms or parisons made of several components at bottom portion
    • B29C2949/3022—Preforms or parisons made of several components at bottom portion partially
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/30—Preforms or parisons made of several components
    • B29C2949/3032—Preforms or parisons made of several components having components being injected
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/0046—Details relating to the filling pattern or flow paths or flow characteristics of moulding material in the mould cavity
    • B29C49/0084—
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
    • B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
    • B29C49/06—Injection blow-moulding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
    • B29C49/071—Preforms or parisons characterised by their configuration, e.g. geometry, dimensions or physical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2067/00—Use of polyesters or derivatives thereof, as moulding material
    • B29K2067/003—PET, i.e. poylethylene terephthalate
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2077/00—Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, as moulding material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/25—Solid
    • B29K2105/253—Preform
    • B29K2105/258—Tubular
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
    • B29K2995/0037—Other properties
    • B29K2995/0065—Permeability to gases
    • B29K2995/0067—Permeability to gases non-permeable
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2009/00—Layered products
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2023/00—Tubular articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/712—Containers; Packaging elements or accessories, Packages
    • B29L2031/7158—Bottles

Definitions

  • This invention relates to a device for injection molding a preform in a shape of a test tube, in which an intermediate layer is laminated with, and embedded in, substrate layers made of a main resin, and especially to a nozzle used in this injection molding device.
  • PET polyethylene terephthalate
  • the bottles to be used are made by laminating an intermediate layer comprising a gas barrier resin, such as a nylon resin, an ethylene-vinyl alcohol copolymer, etc., with substrate layers made of a PET resin, i.e., the main resin, in a manner embedded therein.
  • a gas barrier resin such as a nylon resin, an ethylene-vinyl alcohol copolymer, etc.
  • Patent document D1 describes a biaxially stretched, blow molded bottle, in which an intermediate layer made of a nylon resin is laminated with substrate layers made of a PET resin, and a process for molding a laminated preform in a test tube shape, which is a primary molded product used to mold the bottle.
  • FIGS. 11 and 12 show an example of the bottle described in the patent document D2.
  • This bottle 601 has a neck 602 , a neck ring 603 , a shoulder 604 , a body 605 , and a bottom 606 . As shown in a plane cross-sectional view of FIG.
  • the body wall in a height rage h 2 has a laminar structure, in which an intermediate layer 613 made of a nylon resin is sandwiched between an outer layer 611 a and an inner layer 611 b , both of which are substrate layers 611 made of a PET resin.
  • This bottle 601 is characterized in that the intermediate layer 613 is segmented into 16 strips in this embodiment in a circumferential direction by vertical connecting zones 614 , where the outer layer 611 a is connected directly with the inner layer 611 b to form these vertical zones having no intermediate layer.
  • FIGS. 13( a ) and 13( b ) show an embodiment of the preform in the shape of a test tube, to be used to biaxially stretch and blow mold the above-described bottle 601 , in which FIG. 13( a ) is a front view; and FIG. 13( b ) , a plane cross-sectional view taken along line D-D in FIG. 13( a ) .
  • this preform 501 has a laminar structure in which an intermediate layer 513 made of a nylon resin is laminated with substrate layers 511 made of a PET resin and is segmented by the 16 vertical connecting zones 514 disposed in parallel in a circumferential direction.
  • This preform 501 is molded by utilizing an injection molding device having a nozzle section, in which flow channels are disposed to allow the nylon resin to be formed into the intermediate layer 513 and to laminate it with the substrate layers made of the PET resin.
  • Sixteen vertical blocking rib pieces are disposed in the circumferential direction with equal central angle intervals at an end on the downstream side of a cylindrical middle channel through which the nylon resin flows. These rib pieces inside the nozzle section segment the flow of the nylon resin into small streams in the circumferential direction to form 16 vertical connecting zones 514 in the body of the preform 501 .
  • a left half of the preform 501 shows an area of body wall laminated with the intermediate layer 513 in a cross-hatched pattern.
  • a leading edge, LE that is an uppermost end of the intermediate layer 513
  • a trailing edge, TE that is a lowermost end of the same layer
  • both of the LE and the TE may be located at certain height positions.
  • the leading edge, LE, and the trailing edge, LE there are fluctuations in their height positions to a greater or lesser extent in the circumferential direction.
  • the leading edge, LE for example, may have a difference in height of 10 mm or even more between a maximum height point and a minimum height point.
  • the neck 602 of the bottle 601 shown in FIGS. 11 and 12 is a portion that requires high dimensional accuracy so that no sealing property of the cap would be damaged.
  • the molding conditions are set in such a way that the maximum height point of the leading edge, LE, would come under the position of the neck ring 503 on an average, allowing for some sort of changes in the molding operation.
  • the leading edge, LE would be at levels considerably lower than the neck ring 503 .
  • the preform 501 is stretched in the longitudinal direction generally by about three times in the biaxial stretching and blow molding operation. If the leading edge, LE, is located at 10 mm below the neck ring 503 at points other than the maximum height point, then in the bottle 601 , the leading edge, LE, would be about 30 mm below the neck ring 603 . In that case, a problem arises in that no satisfactory gas barrier property would be acquired.
  • the technical problem of this invention is to minimize fluctuations in the height position of the leading edge of the intermediate layer of the preform in the circumferential direction when the preform is molded by means of a device for molding a preform in the test tube shape by laminating substrate layers of a main resin with the intermediate layer, and especially by means of an injection molding device using a nozzle section in which the intermediate-layer resin is segmented in the circumferential direction into small streams by using a predetermined number of vertical blocking rib pieces that are disposed, in parallel in the circumferential direction, at a downstream end of the middle flow channel through which the intermediate-layer resin flows.
  • a main feature associated with the injection molding device of this invention to solve the above-described technical problem is a device for injection molding a preform in a shape of a test tube used in a biaxial stretching and blow molding operation, in which at least one intermediate layer is laminated with substrate layers made of a main resin, the device having a nozzle section for laminating the main resin with a resin that forms the intermediate layer, said nozzle section comprising:
  • three cylindrical layer-forming flow channels disposed in a coaxial cylindrical configuration which include:
  • flow behavior of the intermediate-layer resin flowing through the middle flow channel is adjusted by positioning the vertical blocking rib pieces in the circumferential direction so as to minimize a difference in height between a maximum height point and a minimum height point that appear in a leading edge of the intermediate layer of the preform.
  • a laminated preform can be formed for use in the biaxial stretching and blow molding operation.
  • the intermediate layer is laminated with the substrate layers to form a laminated area, which extends in a central axial direction and is segmented in the circumferential direction by the vertical connecting zones.
  • This laminated preform can be biaxially stretched and blow molded to form a synthetic resin laminated bottle having the intermediate layer segmented into many strips in the circumferential direction by the vertical connecting zones. Even if delamination takes place in an area due to, e.g., an impact of fall, this delamination can be prevented by the vertical connecting zones from propagating into adjacent areas. Since the delamination is confined to a limited range, the bottle can maintain good appearance and a clear state.
  • the intermediate layer has a thickness of 1 mm at the largest. Because of such a thickness, it is technically difficult to adjust the resin flow behavior to give a uniform flow speed along the circumference by means of clearance adjustment for the cylindrical flow channel or by using a mandrel in a groove shape. It is especially difficult to effectively control any circumferential fluctuation of the time at which the resin reaches the downstream end of the cylindrical middle flow channel.
  • the main feature described above includes a following aspect: “wherein flow behavior of the intermediate-layer resin flowing through the middle flow channel is adjusted by positioning the vertical blocking rib pieces in the circumferential direction so as to minimize a difference in height between a maximum height point and a minimum height point that appear in a leading edge of the intermediate layer of the preform.” This involves utilizing the vertical blocking rib pieces to segment the intermediate layer into small streams in the circumferential direction, and more specifically, utilizing, a difference in resin flow behavior between the positions of the vertical blocking rib pieces and the positions of slits between two adjacent rib pieces, and adjusting the flow behavior of the intermediate-layer resin passing through the cylindrical flow channel, so as to control any circumferential fluctuation of the time at which the intermediate-layer resin reaches the downstream end of the cylindrical middle flow channel.
  • the number and shape of the vertical blocking rib pieces can be determined by giving consideration to an inhibitive effect on the bottle against the progress of delamination between the substrate layers and the intermediate layer, the injection molding property and biaxial stretching and blow molding property of the preform, and the gas barrier property of the bottle. If the injection molding property and the biaxial stretching and blow molding property of the preform are taken into consideration, it is preferred that the vertical blocking rib pieces are disposed uniformly in the circumferential direction at intervals of an equal central angle.
  • the next step is to find what central angle positions on the central axis of the middle flow channel is effective for the predetermined number of vertical blocking rib pieces, which are disposed at certain intervals in the circumferential direction to minimize the high and low height points of the leading edge.
  • These central angle positions can be determined relatively easily by calculating flow states by computer simulation, making experimental samples of the portions constituting the middle flow channel of the nozzle section, based on the results of the simulation, and repeating the experiments.
  • the preform can have various laminar structures, such as 2-resins/3-layers, 2-resins/5-layers, 3-resin/4-layers, 3-resins/5-layers, and the like. This can be achieved by increasing the number of cylindrical flow channels in the nozzle section appropriately within a scope of the feature that both sides of any intermediate layer are laminated with the substrate layers.
  • Another feature of this invention associated with the injection molding device is that, in the main feature described above, a predetermined number of the vertical blocking rib pieces is disposed in the circumferential direction in such a way that one of this number of the vertical blocking rib pieces is located at a circumferential position corresponding to a position where the maximum height point of the leading edge of the preform is likely to appear.
  • the cylindrical middle flow channel has small clearance.
  • the leading edge tends to give a peak of the maximum height point at one location in the circumferential direction of the preform.
  • the circumferential position where the maximum height point of the leading edge of the preform is likely to appear corresponds also to the circumferential position where the resin flowing through the middle flow channel reaches the downstream end in a shortest period of time. If one of the vertical blocking rib pieces is located at a circumferential position corresponding to the position where the maximum height point of the leading edge of the preform is likely to appear, then any possible fluctuation of the time, at which the resin reaches the downstream end of the middle flow channel in the shortest period of time, can be controlled all around the circumference by delaying this time of arrival. As a result, it becomes possible to control the peak height, that is, the minimum height point, of the leading edge and to minimize the difference in height between the maximum height point and the minimum height point that appear in the leading edge of the intermediate layer.
  • the intermediate layer is formed in the middle flow channel.
  • this layer joins the substrate layers formed in the inner and outer flow channels, the intermediate layer is affected by the flow of these substrate layers.
  • both positions are in a relationship of one-to-one correspondence. Therefore, at first, one of the vertical blocking rib pieces is set at a circumferential position similarly corresponding to the circumferential position of the maximum height point of the leading edge. Then, the angular position of this rib piece is finely adjusted. In this manner, all the predetermined number of the vertical blocking rib pieces can be set at positions where the difference in height is minimized reliably between the maximum and minimum height points of the leading edge.
  • Still another feature of this invention associated with the injection molding device is that, in the main feature described above, the vertical blocking rib pieces are disposed in the circumferential direction in such a way that one of the predetermined number of the vertical blocking rib pieces is located at a circumferential position opposed by 180 degrees to the position of an inflow port, which is disposed at an upstream end of the manifold to allow the intermediate-layer resin to flow into the middle flow channel.
  • the inventors of this application acquired the idea of this feature when they discovered that, in many cases, the intermediate-layer resin reaches the cylindrical downstream end most rapidly at a circumferential position opposed by 180 degrees to the position of the inflow port disposed at the upstream end of the manifold and that a maximum height point of the leading edge appears as a peak at a circumferential position of the preform corresponding to this opposite position.
  • the positions of the vertical blocking rib pieces are adjusted in the circumferential direction in such a way that one of the vertical blocking rib pieces is located at a circumferential position opposed by 180 degrees to the position of the inflow port disposed at the upstream end of the manifold, it becomes possible in many cases to control the peak height, that is, the maximum height point, of the leading edge and to minimize the difference in height between the maximum height point and the minimum height point that appear in the leading edge of the intermediate layer.
  • the maximum and minimum height points would have a largest difference in height if a gap between two adjacent rib pieces is located at the circumferential position opposed by 180 degrees to the position of the inflow port, through which the intermediate-layer resin flows into the middle flow channel.
  • the above feature can be the first matter to be checked up in determining the circumferential positions of the vertical blocking rib pieces so as to minimize the difference in height of the leading edge.
  • This invention having the above-described feature has the following effects: “A predetermined number of the vertical blocking rib pieces is disposed in the circumferential direction in such a manner that one out of this number of the vertical blocking rib piece is located at a circumferential position corresponding to the position where the maximum height point of the leading edge of the preform is likely to appear.”
  • This feature involves utilizing the vertical blocking rib pieces to segment the intermediate layer into small streams in the circumferential direction, and adjusting the flow behavior of the intermediate-layer resin passing through the cylindrical flow channel, so as to control any deviation, in the circumferential direction, of the time at which the intermediate-layer resin reaches the downstream end of the cylindrical flow channel.
  • these rib pieces perform an adjusting function on the flow behavior of the intermediate-layer resin, control any possible circumferential deviation of the time, at which the resin passes through the cylindrical flow channel and reaches the downstream end, control the peak height, that is, the maximum height point that appear in the leading edge of the preform, and minimize the difference in height between the maximum height point and the minimum height point.
  • FIG. 1( a ) is a front view, with a part in vertical section, of an embodiment of the preform formed by the injection molding device of this invention; and FIG. 1( b ) is a cross-sectional view taken along line A-A in FIG. 1( a ) .
  • FIG. 2( a ) is a schematic explanatory diagram of the preform in the embodiment of FIG. 1( a )
  • FIG. 2( b ) is that of the preform in a comparative example, both showing fluctuations in the behavior of the leading edge of the intermediate layer.
  • FIG. 3 is a front view of the bottle biaxially stretched and blow molded from the preform of FIG. 1 .
  • FIG. 4 is a cross-sectional view of the bottle of FIG. 3 , taken from line B-B shown in FIG. 3 .
  • FIG. 5 is a vertical section showing the nozzle section of the injection molding device in one embodiment of this invention.
  • FIG. 6 is a vertical section of the nozzle section of FIG. 5 , to which a hot runner block has been fitted.
  • FIG. 7 is a front view of the first ring mandrel that forms the middle flow channel in the nozzle section of FIG. 6 .
  • FIG. 8 is a diagrammatic perspective view taken from an obliquely upward line of sight, which shows a lower portion of the first ring mandrel shown in FIG. 7 .
  • FIG. 9( a ) is a bottom view of the first ring mandrel shown in FIG. 7 ; and FIG. 9( b ) is a bottom view of the first ring mandrel that has been used in injection molding the preform of a comparative example.
  • FIG. 10 is an explanatory diagram showing an example of the injection pattern used to mold the preform of FIG. 1 .
  • FIG. 11 is a front view of an exemplified conventional bottle.
  • FIG. 12 is a front view of a plane cross-sectional view of the bottle taken from line C-C in FIG. 11 .
  • FIG. 13( a ) is a front view, with a right half in a partial vertical section; and FIG. 13( b ) , a plane cross-sectional view, of the preform used in molding the bottle of FIG. 11
  • FIGS. 1( a ), 1( b ), and 2( a ) show an embodiment of the preform 101 molded by the later-described injection molding device of this invention.
  • FIG. 1( a ) is a front view, with a partial vertical section
  • FIG. 1( b ) is a plane cross-sectional view of the preform 101 .
  • FIG. 2( a ) is a schematic explanatory diagram showing fluctuations in the height of the leading edge, LE, of the intermediate layer 113 observed in the circumferential direction.
  • This preform 101 in a shape of a test tube is made by using a PET resin as the main resin, and comprises a neck 102 , a neck ring 103 , a cylindrical body 105 , and a bottom 106 .
  • the laminated areas of the intermediate layer 113 are shown as cross-hatched areas in FIGS. 1( a ) and 2( a ) .
  • This preform 101 has a laminar structure in a predetermined height range h 1 (a height range from right under the neck ring 103 to an upper end of the bottom 106 in this embodiment).
  • the laminar structure comprises an intermediate layer 113 of a gas barrier resin, which is laminated with an outer layer 111 a and an inner layer 111 b , both of which are substrate layers 111 made of the main resin of a PET resin.
  • the gas barrier resin in use is polyxylylene diamine adipamide (MXD6 nylon) (Hereinafter referred to as the nylon resin).
  • MXD6 nylon polyxylylene diamine adipamide
  • the intermediate layer 113 is segmented in the circumferential direction by eight vertical connecting zones 114 , where the outer layer 111 a , a substrate layer 111 , is connected to the inner layer 111 b , another substrate layer 111 .
  • the eight vertical connecting zones 114 are disposed in parallel in the circumferential direction and vertically along the central axial direction.
  • FIG. 1( a ) a leading edge, LE, that is an uppermost end of the intermediate layer 113 , and a trailing edge TE that is a lowermost end of the same layer, are shown in a simplified manner so that both of the LE and the TE may be located at certain height positions. In fact, however, there are fluctuations in these height positions to a greater or lesser extent in the circumferential direction.
  • FIG. 2( a ) is a front enlarged view of an upper half of the preform 101 shown in FIG. 1( a ) and is a schematic explanatory diagram showing fluctuations in the height of the leading edge, LE, of the intermediate layer 113 . As shown in this FIG.
  • the intermediate layer 113 is divided into 8 regions in the circumferential direction by the vertical connecting zones 114 , and each region has a peak of the leading edge, LE, at a laterally central position. If the peaks of all the regions are connected by a dashed-dotted line (also by a dotted line at the rear), an envelope curve L 1 is obtained.
  • a maximum height point, Pmax, of the leading edge, LE comes to the front of the preform 101 in FIG. 2( a ) .
  • a minimum height point, Pmin comes to a rear position opposed by 180 degrees to the front. Other peaks are located between the Pmax and the Pmin, with varied heights.
  • a height difference, hd, between the maximum height point Pmax and the minimum height point Pmin gives an average value of 6.0 mm from the measurements based on many molded preforms.
  • FIG. 2( b ) is another schematic explanatory diagram showing fluctuations in the height of the leading edge, LE, of the preform 101 in a comparative example prepared separately.
  • the height difference, hd reaches a value of 10.0 mm, as calculated from the difference between the maximum height point, Pmax, and the minimum height point, Pmin on the envelope curve L 2 .
  • FIGS. 2( a ) and 2( b ) are typical examples of the fluctuations in the height of the leading edge, LE, in the circumferential direction, in which the maximum height point, Pmax, forms a peak at the front of the preform 101 while the minimum height point, Pmin, is located at the rear, a position opposed by 180 degrees to the front, with other height points showing gradual changes in the circumferential direction between the Pmax and the Pmin.
  • the maximum height point, Pmax forms a peak at the front of the preform 101 while the minimum height point, Pmin, is located at the rear, a position opposed by 180 degrees to the front, with other height points showing gradual changes in the circumferential direction between the Pmax and the Pmin.
  • the height positions of the leading edge, LE are roughly flat in the circumferential direction, with the peak of Pmax appearing at one point on the envelope curve.
  • FIGS. 3 and 4 show an embodiment of the bottle biaxially stretched and blow molded from the preform 101 of FIG. 1 , in which FIG. 3 is a front view, and FIG. 4 is a plane cross-sectional view taken from line B-B in FIG. 3 .
  • This bottle 201 is a so-called pressure resistant PET bottle, which is made by using a PET resin as the main resin and is used as a container, for beverages containing a carbonated ingredient.
  • the bottle comprises a neck 202 , a neck ring 203 , a shoulder 204 , a cylindrical body 205 , and a bottom 206 having a so-called petaloid shape with extended multiple feet.
  • the bottle 201 has a laminar structure having the intermediate layer 213 of a nylon resin sandwiched between the outer layer 211 a and the inner layer 211 b , both of which are the substrate layers 211 made of a PET resin, i.e., the main resin, as shown in the plane cross-sectional view of FIG. 4 .
  • the intermediate layer 213 is segmented in the circumferential direction by eight vertical connecting zones 114 , where the outer layer 211 a , one of the substrate layers 211 , is connected directly to the inner layer 211 b , another substrate layer 211 .
  • the eight vertical connecting zones 214 are disposed in parallel in the circumferential direction and vertically along the central axial direction.
  • the front view of FIG. 3 shows the regions laminated with intermediate layer 213 as cross-hatched areas for the convenience of easy understanding. In fact, however, the intermediate layer 213 is in close contact with the substrate layers, i.e., with the outer layer 211 a or the inner layer 211 b , and the bottle has clear appearance.
  • the bottle 201 of this embodiment has an action-and-effect of the vertical connecting zones 214 that segment the intermediate layer 213 in the circumferential direction into multiple strips (eight in this embodiment). Even if there occurs partial delamination in a strip, these vertical connecting zones 214 can prevent further delamination from proceeding and propagating from one place to another. Since the delamination, if any, only occurs in a limited region or regions, the bottle 201 retains good appearance and remains in a clear state.
  • FIGS. 5-9 show the injection molding device in one embodiment of this invention.
  • FIG. 5 is a vertical section showing an example of the nozzle section 11 , to which a mold 1 has been fitted on the downstream side.
  • FIG. 6 is a vertical section of the nozzle section 11 of FIG. 5 , to which a hot runner block 21 has been fitted on the upstream side.
  • FIGS. 7, 8, and 9 ( a ) are a front view, a perspective view taken from an obliquely upward line of site, and a bottom view, respectively, of the first ring mandrel 24 c that forms the middle flow channel 16 .
  • This injection molding device is used to injection mold the preform 101 shown in FIG. 1 , and comprises resin feeders A, B, which supply two different molten resins separately, the nozzle section 11 where the two molten resins are laminated with each other, and the mold 1 for molding the preform.
  • the nozzle section 11 has three layer-forming flow channels, i.e., the cylindrical inner and outer flow channels 15 , 17 , which form the inner layer 111 b and the outer layer 111 a , both of which are the substrate layers 111 of the preform 101 , and the cylindrical middle flow channel 16 , which forms the intermediate layer 113 .
  • the three flow channels are formed by a combination of a shutoff pin 20 , the first ring mandrel 24 c , a second ring mandrel 24 d , and a third ring mandrel 24 e , all of which are disposed a coaxially cylindrical configuration.
  • the three cylindrical layer-forming flow channels have tapered cylindrical portions at respective downstream ends.
  • FIGS. 7, 8, and 9 ( a ) show a detailed shape of the first ring mandrel 24 c that makes up the inner peripheral wall of the middle flow channel 16 .
  • a manifold 14 b is disposed in a bilaterally symmetric shape and is used as groove-like conduits to distribute the molten resin to the cylindrical flow channel by way of an inflow port 13 b for passing the molten intermediate-layer resin (See also FIG. 6 ).
  • the tapered portion at the downstream end is provided with eight vertical blocking rib pieces 16 R which are disposed in parallel in the circumferential direction at equal central-angle intervals.
  • the eight vertical blocking rib pieces 16 R are disposed in the circumferential direction at equal central angle intervals in such a way that one ( 16 Rb) of the predetermined number of the vertical blocking rib pieces 16 R is set at a circumferential position opposed by 180 degrees to the position of the inflow port 13 b , which is disposed at a position corresponding to the starting point for the manifold 14 b .
  • a bold arrow indicates the direction of resin inflow.
  • FIG. 9( b ) is a bottom view of the first ring mandrel 24 c that has been used to mold the preform in the comparative example shown in FIG. 2( b ) .
  • the eight vertical blocking rib pieces 16 R are shifted by 22.5 degrees from their positions in FIG. 9( a ) showing the first ring mandrel 24 c which is used to mold the preform of the embodiment shown in FIG. 2( a ) .
  • a gap S between two adjacent vertical blocking rib pieces 16 R comes to the circumferential position opposed by 180 degrees to the position of the inflow port 13 b.
  • the preform 101 of this embodiment shown in FIG. 2( a ) and the preform 101 of the comparative example shown in FIG. 2( b ) were injection molded by the same molding device under the same molding conditions, except that the circumferential positions of eight vertical blocking rib pieces 16 R have been shifted by 22.5 degrees. It has been confirmed from a comparison of these two preforms that when the vertical blocking rib pieces 16 R are disposed appropriately in the circumferential direction, the preform 101 of this embodiment shown in FIG. 2( a ) could have a height difference, hd, of the leading edge, LE, that is considerably smaller than found in the preform 101 of the comparative example.
  • one rib piece 16 Rb among the eight vertical blocking rib pieces 16 R is set at a circumferential position opposed by 180 degrees to the position of the inflow port 13 b .
  • that vertical blocking rib piece 16 Rb acts as a baffle plate for the resin flow, and delays the time of arrival for the resin to reach the downstream end at a circumferential position where the arrival of resin is otherwise earliest. It is presumed that this delay holds back the peak height of the maximum height point of the leading edge, LE, which appears in the preform 101 , and minimizes the height difference. Meanwhile, in the case of FIG.
  • a gap S between two adjacent vertical blocking rib pieces 16 R is located at the circumferential position at which the time is earliest for the resin to reach the downstream end.
  • the maximum height point of the leading edge, LE would have a great peak height.
  • the bilaterally central position at the rear of the preform shown in FIGS. 2( a ) and 2( b ) that is, the circumferential position of the minimum height point, Pmin, corresponds to the circumferential position indicated by an arrow in FIGS. 9( a ) and 9( b ) where the inflow port 13 b is located.
  • the main resin of a PET resin is supplied from a resin feeder A, fed into a feed port 22 a , and is passed through the feed channel 23 a inside the hot runner.
  • the intermediate-layer resin of a nylon resin is supplied from a resin feeder B, fed into a feed port 22 b , and is passed through a feed channel 23 b .
  • the two resins are fed into the nozzle section 11 at predetermined timing, are joined inside the nozzle section 11 , and the joined resins are sent to a cavity 1 a of the mold 1 to fill the cavity.
  • a check valve 25 with a function for preventing backflow by means of a ball valve is disposed in the feed channel 23 b at a point near the connection to the nozzle section 11 so that the supply of the intermediate-layer resin can be started and stopped in a short period of time with a high degree of accuracy.
  • the main resin is then passed through a guide channel 12 a which is connected to the feed channel 23 a .
  • the resin flow is branched into two manifolds 14 a 1 and 14 a 2 .
  • the resin entering the manifold 14 a 1 goes into the cylindrical inner flow channel 15
  • the resin entering the manifold 14 a 2 goes into the cylindrical outer flow channel 17 .
  • the intermediate-layer resin is sent from the other feed channel 23 b to a guide channel 12 b , and then at the inflow port 13 b , the resin enters the manifold 14 b and goes into the cylindrical middle flow channel 16 .
  • the intermediate-layer resin coming from the middle flow channel 16 is already layered in a cylindrical shape, and is flowed between the main resin layers from the inner and outer flow channels 15 , 17 .
  • the intermediate layer is disposed between the main resin layers in a coaxially cylindrical configuration over a predetermined period of time to form a multi-layered molten resin fluid, which is injected into the cavity 1 a of the mold 1 to fill the cavity with molten resins (See FIG. 5 ).
  • the intermediate-layer resin which has been layered in a cylindrical shape in the middle flow channel 16 , is segmented in the circumferential direction by the eight vertical blocking rib pieces 16 R disposed circumferentially in parallel at the downstream end of the middle flow channel 16 .
  • the intermediate layer is laminated between the main resin layers in this segmented state.
  • FIG. 10 shows an exemplified injection pattern used for both the main resin and the intermediate-layer resin. It is a schematic diagram depicted with time as the lateral axis and injection speed as the vertical axis.
  • This injection pattern is one of the so-called simultaneous injection molding patterns.
  • the preform 101 shown in FIG. 1 can be molded by using the above-described injection molding device wherein the main resin is injected during a period starting at point C and ending at point D, while the intermediate-layer resin is simultaneously injected during a period starting at point E and ending at point F.
  • the start and stop of the supply of the intermediate-layer resin respectively at point E and point F are performed by a check valve 25 disposed in the feed channel 23 b.
  • one of the vertical blocking rib pieces 16 R is disposed at a position opposed by 180 degrees to the position of the inflow port 13 b that allows the resin to flow into the middle flow channel 16 so that the height difference in the leading edge, LE, would be minimized.
  • the circumferential position, at which the resin runs down the middle flow channel 16 and reaches the cylindrical downstream end in a shortest period of time does not coincide with the position opposed by 180 degrees to the inflow port 13 b due to the effects of groove shape, etc., of the manifold 14 b . Even in such a case, the circumferential position, at which the resin reaches the cylindrical downstream end in the shortest period of time, can be predicted from the circumferential position at which there appears the maximum height point, Pmax, of the leading edge LE.
  • this circumferential position for the resin to reach the cylindrical downstream end in the shortest period of time can be calculated by computer simulation and experiments on the cylindrical middle flow channel 16 , including a groove shape condition for the manifold 14 b . Based on the results of this forecast, the vertical blocking rib pieces 16 R can be disposed appropriately in the circumferential direction.
  • the manifold 14 b shown in FIG. 7 has a structure in which the cross-sectional area of each groove would decrease gradually from upstream to downstream. If the grooves of the manifold 14 b have a constant cross-sectional area ranging from upstream to downstream, then the resin would reach the cylindrical downstream end most quickly at the same circumferential position as that of the inflow port 13 b . Therefore, as shown in FIG.
  • the injection molding device shown in FIGS. 5 and 6 is merely an example. There can be numerous variations within the feasible scope of the subject-matter of this invention.
  • the shape of the manifold 14 b is not limited to the shape shown in the above embodiment, in which groove-like conduits starting from the inflow port 13 b wind obliquely downward in both the left and right directions in a bilaterally symmetric pattern.
  • Other variations can be appropriately adopted, for example, by allowing a groove-like conduit starting from the inflow port 13 b to go winding obliquely downward only in one direction, while giving consideration to the viscosity of the molten intermediate-layer resin.
  • factors to be considered include the number and shape of the rib pieces and what place the rib pieces are disposed in at the downstream end of the middle flow channel 16 , etc. These factors can be determined appropriately, while giving consideration to an inhibitive effect of the vertical connecting zones on the progress of delamination between the substrate layers and the intermediate layer in the body of the bottle, the injection molding property and the biaxial stretching and blow molding property, of the preform, and the gas barrier property of the bottle.
  • the preform in the above embodiment has a laminar structure of 2-resin/3-layers, as shown in the plane cross-sectional view of FIG. 1( b ) .
  • the preform can have various laminar structures, such as 2-resins/3-layers, 2-resins/5-layers, 3-resin/4-layers, 3-resins/5-layers, and the like. This can be achieved by increasing the number of cylindrical flow channels in the nozzle section appropriately within the scope of the feature that both sides of any intermediate layer are laminated with the substrate layers.
  • the above embodiment uses a PET resin as the substrate resin and a nylon resin as the intermediate-layer resin.
  • FIGS. 3 and 4 show a round bottle, it is also possible to mold a square or rectangular bottle. Since in that case, the bottle shape is not isotropic, the positions of a multiple number of the vertical connecting zones can be determined in the circumferential direction, while considering angular positions where delamination tends to occur, and not the intervals based on an equal central angle, such as shown in FIGS. 3 and 4 .
  • the delamination between the substrate layers and the intermediate layer can be inhibited from proceeding. Moreover, it becomes possible to provide a bottle having a laminar structure in which the leading edge of the intermediate layer has a minimized height difference between the maximum and minimum height points. Thus, a wide variety of use applications are expected in the fields of carbonated beverages.

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WO2014207986A1 (fr) 2013-06-28 2014-12-31 株式会社吉野工業所 Dispositif de moulage par injection de préformes
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US20140287079A1 (en) 2014-09-25
EP2774741A1 (fr) 2014-09-10
EP2774741A4 (fr) 2015-07-15
CN103379987A (zh) 2013-10-30
WO2013065501A8 (fr) 2013-07-04
WO2013065501A1 (fr) 2013-05-10
AU2012333790A1 (en) 2014-05-08
CA2853504C (fr) 2019-05-14
CA2853504A1 (fr) 2013-05-10
ZA201403120B (en) 2015-11-25
EP2774741B1 (fr) 2019-01-02
JP2013095035A (ja) 2013-05-20
KR102036527B1 (ko) 2019-10-25
AU2012333790B2 (en) 2017-09-07
KR20140086924A (ko) 2014-07-08
CN103379987B (zh) 2016-04-06
JP5765656B2 (ja) 2015-08-19

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